Home » Origin of ion-cyclotron turbulence in the downward Birkeland current region

TITLE

Origin of ion-cyclotron turbulence in the downward Birkeland current region

AUTHOR(S)

Basu, B.; Jasperse, J. R.; Lund, E. J.; Grossbard, N.

PUB. DATE

February 2011

SOURCE

Physics of Plasmas;Feb2011, Vol. 18 Issue 2, p022901

SOURCE TYPE

Academic Journal

DOC. TYPE

Article

ABSTRACT

Linear stability analysis of the electron velocity distributions, which are observed in the FAST satellite measurements in the downward Birkeland current region of the magnetosphere, is presented. The satellite-measured particle (electrons and protons) velocity distributions are fitted with analytic functions and the dispersion relation is derived in terms of the plasma dispersion functions associated with those distribution functions. Numerical solutions of the dispersion relation show that the bump-on-tail structure of the electron velocity distribution can excite electrostatic ion-cyclotron instabilities by the Landau resonance mechanism. Nonlinear evolution of these instabilities may explain the observed electrostatic ion-cyclotron turbulence in the Birkeland current region. Excitation of other types of instabilities by the fitted electron velocity distributions and their relevance are also discussed.

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